Hot-air heating furnace



J.'W. DUPUY HOT AIR HEATINQ F-URNACE Filed Jan. 1l

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J. w, DUPUY Ho'r A'IR HEATING FURNACE Filed Jan. ll, 1925 3 SheetS-Sheet 2 March 4 1924.

J. -W. DUPUY HOT AIR HEATING FURNACE Filed Jan. 11. `1923 s' sheets-sheet S IN V ENTOR.

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Patented Mar. 4, 1924.

UNITED STATES Param i omen- HOT-AIR; HEATING FURNACE.

Application led January 11, 1923.

Tol all whom t may concern.'

Be it known that I, JOHN IV. DUPUY, a citizen of the United States, and residing in the borough of Beaver Falls, in the county of Beaver and State of Pennsylvania, have invented or discovered the new, useful, and Improved Hot-Air I-Ieating Furnace, lof which the following is a speciication.

My invention consists in certain new and useful improvements in hot air heating furnaces.

The objects which I have in view are economy in fuel, more complete utilization of the heating value of the same, and complete smoke consumption. y

Generally speaking my improved furnace presents the following characteristic structure.

The combustion chamber 'dome is surrounded by the radiator dome, the former having an exit orifice 'for the .products of combustion in its top through which the furnace gases pass into the radiator dome. In the radiator dome the gases are caused to pass down around and entirely envelope the combustion chamber before they are permitted to escape to the chimney flue. Means are also provided for mixing oxygen with the furnace vgases as they enter the radiator dome, thereby facilitating the combustion of the gasesr in the radiator dome.

I thus provide a primary combustion chamber and, surrounding the latter, a secondary `combustion chamber in which the combustion of the gases is complete.

The furnace casing is spaced away from the furnace proper for its full circumference, thus using the entire furnace surface for radiation, and preventing direct radiation to the exterior of the casing and the consequent waste of heat. I

Other novel features of construction and arrangement of parts will appear from the following description.

In the accompanying drawings, which are however merely intended to illustrate a -practical embodiment of the principles of my invention without limiting the scope of the latter to the construction shown, Fig. -1 is a diametric section of the casing with the furnace shown partially Iin section; Fig. 2 is a diametric section of the furnace and casing taken at right angles to Fig. 1;' Fig. 3 is a horizontal section taken along the line III-III inFigQQ; Fig. 4 is a top View Serial No. 611,944.

of the radiator dome baiie plate; Fig. 5 is aV plan view of the radiator dome bottomV plate; Fig. 6 is a horizontal section taken along the line VI-VI in Fig. 2; Fig. 7 is an enlarged detail in vertical'section of the hot blast nozzle, and Fig. 8 is a horizontal section taken along the line VIII-VIII in Fig. 7.

The following is a detailed description of the drawings. Y

A is the base which sits on the floor and is provided with the forward Vextension 1 whichr forms the 4ioor of the ash-mouth.

B is the base ring for the casing, which encircles the base A and is held in proper relation thereto by the struts 2. At they front the base ring is supported by the extension 1 of the base.

C is the ash-pit section whose lower edge is stepped in the perimetral trough-flange 3 of the baseA., thus forming av cup joint which is packed with asbestos putty, the

ends of said flange 3 being extended for-V wardly along the side edges of the extension l Yto receive the bottom edges of the extension 4L of the ash-pit section which form the side walls of the ash-mouth. The roof of the ash-mouth is formed by a hori zontal portion 5 of the ash-pit section.

D isthe fire pot, shown provided with vertically disposed exterior and interior strengthening ribs 6. The .fire pot is mounted on the ash pit, the lower edge of the former seating into the trough-flange 7 of the latter. 1

E is a horizontally disposed, annular' radiator dome bottom plate which is mounted on the top of the fire pot. Said plate E is shown in plan in Fig. .5. The inner perimeter of said plate E is provided with a continuousinverted trough-flange 8 which seats Yon .the top edge of the fire pot. 9 is a vforward extension of the lflue plate, which forms the floor of the fuel-mouth. The inner perimetral edge of the plate E isV lalso provided with Yan upwardly 'disposed trougli-flange l0 which is not continuous at the front but is extended forwardly, as shown at 10a, along either side of the extension 9 to the frontend of the latter.

The outer vperimetralV 'edge of the plate E is also provided with an upwardly disposed trough-flange 1'1 which at the front joins the forwardly extending ends Vof. the trough-v flange-1Q, an odset Y12 being provided at said .junctions for va'purpose to be described.

F is the fuel-section which forms the primary combustion chamber. Said section F is supported by its lower edge seating in the trough-ange ot the plate E. At the front, the section F is provided with a forward extension 13, forming the fuel opening and the inner portion ot the fuelmouth. rl`he bottom edges of said extension seat in the forward extension 10a ot the trough-flange 10 as far Vas the junctions with the ends of the trough-flange 11.

" rlhe section F is domed and has a central orifice 14 for the escape of gases, said oriiice being rimmed with a bead 15 to increase its strength to resist the edects of expansion and contraction@ G is the lower radiator dome section, supported by having its lower edge seated in the trough-liange 11 ofthe bottom plate E.

At the front said section G is provided with Y an extension whose side walls 16 are stepped in the extensions of the trough-flange 10 in front of the extension 13 ot the section F. The top wall 17 ot the extension of the section G Jforms the roof of the outer portion ot the fuel mouth. The inner vertical edges y of the walls 16 and the inner horizontal thus edge of the wall 17 are provided with an angular shoulder 18 which iits over the edges of the extension 13 of the section F, forming a tight joint. The oiisets 12 in the trough-flange .11 provide clearance for the lower ends of such shoulder 18.

H is the upper radiator dome section, which has a closed top and which is supported in place by its lower edge seating in thetrough-flange 19 of the section G.

The space inclosed between the radiator dome sections G and H as its outer top wall, the section F as its inner wall and the plate E as its bottom wall, forms the secondary combustion chamber into which the gases pass from the primary combustion chamber through the orifice 1li.

At its lower rear the section G is provided with a clean-out pipe 21 having a check-damper 22. 23 represents the fumesescape pipe which leads from the top rear of the section H. rlhe rear portion of the secondary combustion chamber, adjacent to the escape pipe 23 is out od from thek remainder of the secondary combustion chamber by the baffie I. Such battle entirely closes od the space except for ports or passages directly above the flue-plate E. The preferred form of said baie is illustrated in Figs. 1, 2 and 3, the center ot the battle, 24C, being rearwardly convexed, while its sides 25 are angled rearwardly. At the top the baiiie is provided with a 'forwardly extending pierced ear 26 which is anchored to the top of the unit H by a bolt 27 which extends through a hole in the top of said unit. The exterior surface of the section F is provided with a trough-flange 28 of proper contour to receive the lower edge of the'baiiie, thus further anchoring it in position. 29 represents a port at each side Jformed between the bottom edge of the side 25 of the batiie and the flue plate E, thus permitting the fumes to pass down under the battle to the rearthereot where they pass upward y in the rear of the baffle to the escape pipe 23. r)The combined capacity ot the ports 29 is substantially equal to that ot the escape pipe 23. rlhe baffle yplate l thus forms a goose-necir iiue within the radiator dome.

rShe trougl -tianges, in which the various parts are stepped form cup joints which are supplied with asbestos putty or other packing to render the saine gas-tight.

K is the vertically disposed 'front plate, preferably a casting, and bolted to the ash and tuel mouths. Said front plate is shown provided with an ash-door 30; a water tank 31, and a fuel door 32.

L is a hot blastpipe whose outer and horizontal end is connected to a port 33 in the upper portion of the 'front plate K, said port being provided with a rotary shutter valve 3ft. The inner and vertical end of said pipe extends down through the port 2() in the top 'ot the uniti-l and is provided with a removable nozzle M, which may be replaced when burned oil.

Thus, l show the lower end ot the pipe L provided with an internal flange 35 which is apertured or interrupted at two or more points, as at 36. rlhe upper end ot the nozzle M is provided with a similar number of correspondingly positioned radial lugs 37. rlhus by turning the lugs into registration with the interruptions 36 or the flange 35, the upper end of the nozzle kmay be inserted up into said pipe. r1`he nozzle is then rotated to turn the lugs out ot registration with the interruptions, thus supporting and locking the nozzle on the pipe. rlhe lower end ot the nozzle is positioned about tour inches above the orifice 14.

Where hard coal is the tuel used, the valve 34 is kept closed.

1n a furnace provided with a twenty-two inch tire pot, the primary combustion chamber is about twelve inches in height and the radiator dome about twenty-two inches in height and thirty inches in diameter, while clearance between the primary combustion chamber dome and the radiator domeat the bottom plate is about four inches.A rlhe hot blast nozzle extends down to about four inches above the oriiice 1li, the space between the two domes being ten inches.

N is the lower casing section which is mounted on the ring B. O is the intermediate casing section mounted by means of the interposed casing ring 38 on the section N, and P is the upper Ycasing section similariy mounted on the section G.' Q is the casing dome mounted on the section P and the front plate L. The ends of the sections N, O and P areattached in the usual manner to the front plate L. The casing dome Q may be provided with flanged ports 39 for hot-air pipes.

40 represents the usual dust pipe which connects the-ash-mouth with the fuel mouth.

it is evident that the gases from the combustion of the fuel in the ire pot ascend into the primary combustion chamber and pass up through the orifice 14C in the top thereof, and then are prevented by the baffle from passing directly to the escape pipe and directed down within the secondary .combustion chamber around the exterior wall of the primary combustion chamber to the flue-plate E. Y

Thus the combustible parts of such gases as are not consumed in the primaryv combustion chamber are subjected to super-heating in the secondary combustion chamber and are entirely consumed. The fumes which reach the escape pipe 9.3 are substantially free ofV combustibles and theiry full heating value utilized. The hot blast adds oxygen to the gases as they enter the secondary combustion chamber, thereby insuring their complete and final combustiomand causing the primary combustion chamber to be bathed in the most intense heat which also acts to improve combustion in the primary combustion chamber.

Thus the secondary combustion chamber presents a highly heated radiating surface to the air passing upwardly within the casing, the secondary combustion chamber presenting practically its entire exterior surface for radiation, as the annular air space around the secondary combustion chamber is interrupted only by the ash andy fuel mouths and the hotY blast pipe.

The gases as they enter the secondary combustion chamber are not split or divided, as is usually the case, but are massed in an integral volume in the radiating chamber. Thus, their heat is not dissipated or divided but is maintained to promote complete' combustion.

Although, for the sake of clearness in illustrating the practical embodiment of the principles of my invention shown in the drawings, have described the same in detail, l do not wish to limit myself thereby, but claim broadly l. in a hot air heating furnace, the combination of a primary combustion chamber receiving the products of combustion from the lire pot, a secondary combustion cham- Jer surrounding said primary combustion chamber and formiruT a tight closure over the top of the same, the top of said primary combustion chamber being provided with an orifice opening into' said secondary combustion chamber and which :EcrinsI anV escape port through which the furnace gases pass upwardly fromk the primary combustion chamber into the secondary combustion chamber, and an escape port for the furnace gases from the secondary combustion chamber. v

2. In a hot air heating furnace, the combination of a primary combustion chamber receiving the products of combustion from the fire pot, a secondary combustion chamber surrounding said primary combustion chamber and. forming a tight closure over the top of the same, the exterior wall of the primary combustion chamber forming the interior wall of the secondary combustion chamber, the top of said primary combustion chamber being provided withan orifice opening into said secondary combustion chamber and which forms an escape port through which-the furnace gases pass upwardly from the primary combustion chamber into the secondary combustion chamber, and an escape port for the furnace gases from the secondary combustion chamber.

3. In a hot air heating furnace, the com bination of a primary combustion chamber receiving the products of combustion from the fire pot, a secondary combustion chamber surrounding said primary combustion chamber and receiving the furnace gases therefrom, the top of the primary combustion chamber being provided with an orifice through which the products of combustion pass upwardly into the secondary combustion chamber, a fumes escape for said secondary combustion chamber, and a baffle in said secondary combustion chamber whereby the gases are caused to envelope said primary combustion chamber before reaching said escape.

4. In a hot air heating furnace, the combination of a primary combustion chamber receiving the products of combustion from the fire pot, a secondary combustion chambersurrounding said primary combustion chamber Vand receiving the furnace gases therefrom, the top of the primary combustion chamber being provided with an orifice through which the products of' combustionv pass upwardly into the secondary combustion chamber, the inner wall of said secondary combustion chamber forming the outer wall of said. primary combustion chamber, a. fumes escape for said secondary combustion chamber, and a baffle in said secondary combustion chamber whereby the gases are caused to envelope said primary combustion chamber before reaching said escape.

5. In a hot air heating furnace, the combination of a primary combustion chamber receiving the productsy of combustion from lthe fire pot, a secondary combustion, chamber surrounding said primary combustion chamber and receiving the furnace gases. therefrom, the,A top of the combustion chamber being provided with an orifice through which the products of combustion pass upwardly into the secondary combustion chamber, and means for adding oxygen from without the furnace to the gases as they enter the secondary combustion chamber.

6. ln a hot air heating furnace, the combination of a primary combustion chamber receiving the products of combustion from the fire pot, secondary combustion chamber surrounding said 4primary, combustion chamber and receiving the furnace gases therefrom, the' top of the primary combustion chamber being provided with an orifice through which the products of combustion pass upwardly into the secondary combustion chamber, the inner wall of said secondary combustion chamber forming the outer wall of said primary combustion chamber, and means for adding oxygen from without the furnace to the gases as they enter the secondary combustion chamber.

7. in a hot air heating furnace,'the combination of a primary combustion chamber receiving the products of combustion from the fire pot, a secondary combustion chamber surrounding` said primary combustion chamber and receiving the furnace gases therefrom, the top of the primarf combustion chamber being provided with an orifice through which the products of combustion pass upwardly into the secondary combustion chamber, and a hot blast discharging air into the gases as they enter the secondary combustion chamber.

8. In a hot air heating furnace, the combi nation of a primary combustion chamber receiving the products of combustion from the fire pot, a secondary combustion cham-v ber surrounding said primary combustion chamber and receiving the furnace gases therefrom, the top of the primary combustion chamber being provided with an orifice through which the products of combustion pass upwardly into the secondary combustion chamber, the inner wall of said secondary combustion chamber forming the outer wall of said primary combustion chamber, and a hot blast discharging air into the gases as they enter the secondary combustion chamber.

9. fn a hot air heating furnace, the combination of a combustion dome mounted on the fire pot and having a discharge orifice in its top, a radiator dome surrounding said combustion dome and forming a spaced enclosure extending over the top of said dome and forming therewith a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome, and a furnace escape for said secondary combustion chamber.

l0, iin a hot air heating furnace, the combination of a combustion dome mounted on the fire pot and having a dischargeorifice in its top, ay radiator dome surrounding said combustion dome and forming a spaced enclosure extending over the topv of said Vdome and forming therewith a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome, a fumes escape for said secondary combustion chamber, and means whereby the furnace gases are caused to envelope the combustion dome in their travel to said fumes escape.

11. In a. hot air heating furnace, the combination of a combustion dome mounted on the fire pot and having a discharge orifice f in its top, a radiator dome surrounding said combustion dome and forming a spaced enclosure extending over the top of said dome and forming therewith a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome, and a baffled escape passage for the fumes from said secondary combustion chamber.

l2. In a hot air heating furnace, the combination of a combustion dome mounted on the fire pot and having a dischargeorifice in its top, a radiator dome surrounding said combustion dome and forming therewith a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome, and means for adding air to the furnace gases as they leave the combustion dome.

13. In a hot air heating furnace, the combination of a combustion dome mounted on the fire pot and having a disch arge orifice in its top, a radiator dome surrounding said combustion dome and forming therewith a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome, and a hot blast pipe extending into said secondary combustion chamber above said orifice.

14:. In a hot air heating furnace, the combination of a primary combustion chamber mounted on the fire pot and receiving the products of combustion therefrom, a secondary combustion chamber surrounding said primary combustion chamber and extending over said primary combustion chamber to form a top enclosure spaced above the latter, and into which the products of combustion pass upwardly through said orifice from the primary combustion chamber, the inner wall of the secondary combustion chamber forming the outer wall of the primary combustion chamber, and an outer furnace casing spaced from said sec-V ondary combustion chamber for the full circumference thereof.

15, fn a hot air heating furnace, the combination of a primary combustion chamber mounted on the fire pot and receiving the products of combustion therefrom, a secondary combustion chamber surrounding said primary combustion chamber and eX- tending over the same in spaced relation thereto to form a tight top closure, and said secondary combustion chamber being connected to the primary combustionchamber through an orifice in the top of the latter through which orifice the products of combustion pass upwardly into said secondary combustion chamber, and an outer furnace casing spaced from said secondary combustion chamber for the full; circumference thereof.

16. In a hot air heating furnace, the combination of a fire pot, a combustion dome mounted on said fire pot and having an aXial orifice in its top, and a radiator dome mounted on said fire pot and inclosing said combustion dome circumferentially and above said dome and spaced away therefrom, the space between said domes forming a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome.

17. In a hot air heating furnace, the combination of a fire pot, a combustion dome mounted on the fire pot and having an axial orifice in the top thereof, a radiator dome mounted on said fire pot and inclosing said combustion dome and spacedv away therefrom, the space between said domes `forming a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome, and a hot blast discharging into said radiator dome adjacent to said orifice.

18. In a hot air heating furnace, the combination of a fire pot, a combustion dome mounted on the fire pot and having an orice in the top thereof, a radiator dome mounted on said fire pot and inclosing said combustion dome and spaced away therefrom, the space between said domes forming a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome, and a baffled fumes escape in said radiator dome.

19. In a hot air heating furnace, the combination of a fire pot, a radiator dome bottom plate mounted on said fire pot, a combustion dome mounted on said bottom plate and having an orifice in its top, a radiator dome enveloping said combustion dome circumferentially and over the top `of said dome and mounted on said bottom plate, said radiator dome being spaced from said combustion dome to form a secondary combustion chamber into which the products of combustion pass upwardly through said orifice from said combustion dome, and a fumes escape from said secondary combustion chamber.

20. In a hot air heating furnace, the combination of a fire pot, a radiator dome bottom plate mounted on said fire pot, a combustion dome mounted on said bottom plate and having an orifice in its top, a radiator dome enveloping said combustion dome and mounted on said bottom plate, said radiatorI dome being spaced from said combustion dome to form a secondary combustion chamber, a fumes escape from said secondary combustion chamber, and means whereby the gases are caused to envelope said combustion dome before reaching said escape.

21. In a hot air heating furnace, the combination of a fire pot, a radiator dome bottom plate mounted on said fire pot, a combustion dome mounted on said bottom plate and having an orifice in its top, a radiator dome enveloping said combustion dome and mounted on said bottom plate, saidradiator dome being spaced from said combustion dome to form a secondary combustion chamber, a fumes escape in the upper side wall of said secondary combustion chamber, and means whreeby the gases are caused to pass downwardly in said secondary combustion chamber and envelope said combustion dome before they reach said fumes escape.

Signed at Pittsburgh, Pa., this 8th day of January, 1923.

JOHN W. DUPUY. 

